Think you've been pretty good about eating well but find you're still not losing weight? Beware these hidden sources of calories, which can mean diet sabotage despite your best intentions.

Oversized portions: The calories listed on the package are the amount contained in a specific amount of food, but that's not necessarily the amount you're eating. For example, your box of cereal may list a one-cup serving as having 120 calories. But if your bowl holds 2 cups of cereal and you're filling it, you're actually getting 240 calories. Oversized restaurant servings are also a major culprit. So familiarize yourself with proper portion sizes by measuring and weighing out your food - and don't be afraid to ask for a doggie bag when you go out.

Oversized products: It's not just the foods you dish out yourself that are big. Bagels, muffins, and other "single-serving" foods are also growing in size and making you do the same. Some pack 4 servings of bread into just one piece.

The salad bar: Think opting for salad for lunch is a diet-friendly choice? If you load up on veggies and a small amount of dressing, you're right. But if you pile on creamy coleslaw and pasta salads, creamy dressings, or salads swimming with oil, you're loading up on extra calories. Toppings such as bacon bits, croutons, and Chinese noodles can also take your salad from a dieter's dream to a dieter's nightmare.

Liquid calories: Obviously regular pop and other soft drinks are loaded with sugar. But even if you are guzzling down juice and congratulating yourself for making a healthy choice, you are getting more calories than you need. Juice is a good source of vitamins, but it's also a great source of calories - 8 ounces of orange juice, for example, rings in at around 110 calories. The problem with drinking your calories, however, is that the body doesn't seem to register them the same way as it does food, so while a 100-calorie snack can make a dent on your appetite and reduce the number of calories you consume later, a drink won't. And if you are drinking soft drinks sweetened with fructose, there is some evidence that this sweetener causes changes in metabolism that promote the body to store more fat.